  Diagnostic strategy for identifying avian pathogenic Escherichia coli based on four patterns of virulence genes; ; et al in Journal of Clinical Microbiology (2012), 50(5), 1673-1678 Detailed reference viewed: 11 (1 ULg) Common virulence factors and genetic relationships between O18 : K1 : H7 Escherichia coli isolates of human and avian origin; ; et al in Journal of Clinical Microbiology (2006), 44(10), 3484-3492 Extraintestinal pathogenic (ExPEC) Escherichia coli strains of serotype 018:K1:H7 are mainly responsible for neonatal meningitis and sepsis in humans and belong to a limited number of closely related ... [more ▼] Extraintestinal pathogenic (ExPEC) Escherichia coli strains of serotype 018:K1:H7 are mainly responsible for neonatal meningitis and sepsis in humans and belong to a limited number of closely related clones. The same serotype is also frequently isolated from the extraintestinal lesions of colibacillosis in poultry, but it is not well known to what extent human and avian strains of this particular serotype are related. Twenty-two ExPEC isolates of human origin and 33 isolates of avian origin were compared on the basis of their virulence determinants, lethality for chicks, pulsed-field gel electrophoresis (PFGE) patterns, and classification in the main phylogenetic groups. Both avian and human isolates were lethal for chicks and harbored similar virulence genotypes. A major virulence pattern, identified in 75% of the isolates, was characterized by the presence of F1 variant fimbriae; S fimbriae; IbeA; the aerobactin system; and genomic fragments A9, A12, D1, D7, D10, and D11 and by the absence of P fimbriae, F1C fimbriae, Afa adhesin, and CNF1. All but one of the avian and human isolates also belonged to major phylogenetic group B2. However, various subclonal populations could be distinguished by PFGE in relation to animal species and geographical origin. These results demonstrate that very closely related clones can be recovered from extraintestinal infections in humans and chickens and suggest that avian pathogenic E. coli isolates of serotype 018:K1:H7 are potential human pathogens. [less ▲] Detailed reference viewed: 22 (6 ULg)Pathogenicity of pap-negative avian Escherichia coli isolated from septicaemic lesions; ; Mainil, Jacques  et alin Microbes & Infection (2004), 6(7), 637-645 Recent studies by DNA-DNA hybridisation assays conducted on a large collection of Escherichia coli strains isolated from chickens, ducks and turkeys suffering from colibacillosis, showed that 76% of the ... [more ▼] Recent studies by DNA-DNA hybridisation assays conducted on a large collection of Escherichia coli strains isolated from chickens, ducks and turkeys suffering from colibacillosis, showed that 76% of the strains were negative for the presence of the pap gene cluster. The objective of this paper was to study the virulence associated with the avian E. coli strains negative for the P fimbriae, but carrying the f17 or the afa-8 gene cluster coding for adhesins associated with strains pathogenic for mammals. Three strains carrying the f17 fimbriae and three carrying the afa-8 adhesin-encoding gene cluster were studied in three in vivo experimental models of avian colibacillosis: subcutaneous inoculation of 1-day-old chicks, inoculation of specific-pathogen-free (SPF) chickens via the intra-thoracic air sac, and intra-tracheal inoculation of axenic chickens. The results showed that the six P-negative E. coli isolates carrying the f17 or the afa-8 gene cluster were lethal for 1-day-old chicks. They were also able to reproduce clinical signs and lesions of colibacillosis (aerosacculitis, pericarditis, perihepathitis), with bacteraemia and septicaemia, in SPF chickens inoculated via the thoracic air sacs as well as in axenic chickens inoculated by the intra-tracheal route. Further studies with f17 and afa-8 allelic mutants constructed by disruption must be performed to confirm a role of F17 fimbrial and Afa-VIII afimbrial adhesins in the pathogenesis of avian colibacillosis. (C) 2004 Elsevier SAS. All rights reserved. [less ▲] Detailed reference viewed: 23 (1 ULg) |
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